Industrial waste water as well water-borne waste and paints derived from industrial processes such as electrophoretic and spray-booth painting can cause serious pollution problems. Water-born paints, and waste water when discharged as aqueous carrier with paint or lacquer residues, increase substantially the chemical oxygen demand (COD). Such paint and lacquer deteriorate by ageing or chemical modification, become sticky or hard, resulting in pipe and equipment blockage which are extremely difficult to clear.
In addition to the prior art disclosed in U.S. patent application Ser. No. 842,515, filed on Mar. 21, 1986, the following prior art patents are related to the subject matter of this application:
U.S. Pat. No. 4,067,806 of Frank A. Mauceri discloses a process of detackification of paint and spray booth lacquer by using amphoteric salts (like zinc chloride etc.) and a terpolymer-"graft"-on diallyldimethylammonium halide, N-vinylpyrrolidone and acrylamide. The compositions have tremendous disadvantage by using amphoteric salts like ZnCl.sub.2, which will form zinc hydroxide only at high pH of 10 to 10.5. Below and above this pH range, the zinc hydroxide is soluble again, so the floc forms. On the other hand, the zinc hydroxide is very fluffy and unstable, and absorbs much water which makes the products very unsecure in this kind of application. The waste water and the sludges are alkaline and can not be discharged without further treatment, which makes such processes uneconomical. Further, under the conditions described in the patent, the amphoteric salt (ZnCl.sub.2) can easily be transformed into inactive anion like ZnCl.sub.3).sup.- by the reaction: ##STR2## which decreases the efficiency to treat and/or kill the anodic and/or cathodic paints, lacquer, etc.
U.S. Pat. No. 3,990,986 of Gabel, et al, like Mauceri, teaches detackification of the paint and lacquer by using amphoteric salts (like ZnCl.sub.2) or a blend with alkanolamines and/or aliphatic amino alcohols. This patent presents the same negative aspects as Mauceri. Note also that the test conditions of detackification use an insufficient amount of paint (0.5 cc/500 mls of water) for a fair test. The product selected, such as polyalkylene oxide with molecular weight (Mw) of 200 has low Tg (glass transition temperature) which makes the reaction hydrophilic, resulting in very unsecure floc, and the paint may be only partially killed.
U.S. Pat. No. 4,401,574 of Farrington, et al, uses polyaluminum chloride (PAC) in paint waste water, such as polyvinylacetate latex based paint or vinyl-acrylic paint. The (PAC) alone or mixed with regular aluminum and/or iron salts (chloride, sulfate) are totally ineffective on air-borne paint and lacquer waste water treatment. Even in regular paint waste water, the water clarity (35 NTU) is still hazy.
U.S. Pat. No. 4,182,839 of Tesson discloses the process of manufacturing cationic resin soluble in water, based on melamine formaldehyde-alkyl and/or alkanolamine-hydrochloric acid. The products are used in the paper industry, to develop resistance of paper to humid conditions.
U.S. Pat. No. 3,645,841 of Jean A. Cabestany et al discloses a process of producing cationic quaternized resin by reacting melamine-formaldehyde-dimethyl sulfate. The products are used in paper industry applications.
Electrophoretic paints consist of an organic substrate on which ionic charges have been introduced. Today's market can offer anodic electropaints or a cathodic formulation. For more than twenty years, the method of treatment has been to add a chemical coagulant (either ferric or aluminum salts) in a controlled pH environment to form a hydrous oxide floc onto which that paint can be adsorbed. The anodic paints become sticky if they encounter acid conditions and cathodic paints become sticky in alkaline conditions. Application of solvent-based paints by spraying, followed by a hardening stage is extensively practiced for motor car body finishes over the electropaint primer. The spraying is carried out in a booth with exhaust system to extract surplus air-borne paints. Any removed material passes through a curtain of recirculating water, which will absorb paint and solvent, and which has to be removed before the waste water is recirculated.
The most common paints used are classified into two groups:
a. Spray-booth paints such as thermosetting acrylic clear-coat, thermosetting acrylic enamel, thermoplastic acrylic lacquer and stoving alkyd. PA1 b. Electophoretic paints such as acrylic based anodic, epoxy-based cathodic and polybutadiene based anodic. PA1 1. Epoxy, such as pre-polymerized epoxy resin, amide-epoxy (crosslinked copolymers). PA1 2. Styrenated alkyd PA1 3. Drying oils PA1 4. Phenolic resin PA1 5. Urea alkyd PA1 7. Urea melamine PA1 7. Silicone PA1 a. Any inorganic and/or organic alkaline matter such as NaOH, KOH, Ca(OH), sodium aluminate, potassium aluminate, sodium zincate, sodium silicate and/or metasilicate, sodium borate, alkyl amines, alkanol amines or mixture of these in combination with "hydrophobe" materials. PA1 b. (Co)polymers, surfactants (preferably nonionics and/or anionics and/or mixture of these from 0.5% b.w.-95.5% b.w.-0.5% b.w.). The most preferable hydrophobe product are the (co) polymers such as cationic polyamines or copolymers, or vinyl latex type as ethylenicaly, styrene latex, styrene-divinylbenzene latex, styrene butadiene (modified) latex, styrene acrylates and/or acrylic latex, acrylates and/or natural polymers type. PA1 c. Hydroxy alkyl(poly)carboxylate salts and/or acids such as sodium gluconate, sodium gluco heptonate, modified natural (co)polymers salts, sodium rosinates, sodium glucosides and/or other cation combinations, clay and bentonite modified inorganic and/or organic type including cationic types. PA1 d. Other products used can be in any forms as inorganic/ or organic alkaline stripper agents including halogenated types and/ or in combination with products (a), (b) and/or (c). PA1 1. Quaternization of a monomeric compound, e.g. a vinyl monomer or epoxide, and subsequent polymerization. PA1 2. Quaternization of tertiary amine with halogenated polymer. PA1 3. One-step spontaneous polymerization of unsaturated tertiary amine (e.g. vinyl pyridine) with alkylating agents. PA1 4. Quaternization of polyamine with alkyl halide. PA1 5. Polymerization of di(tertiary amine) and alkylene dichloride to form (poly)ionenes or polymerization of chloroalkyl tertiary amine to form (poly)ionenes. PA1 6. Post reaction of polymer containing suitable reactive functional groups with quaternary ammonium compounds. PA1 (A) ##STR5## as described. Component A PA1 Me.sup.II is a divalent cation selected from the group comprising: Mg, Zn, Ca, Fe .sub.2 +; and m to=0 to 5 PA1 Me.sub.n.sup.III is a tri- or more valent metal, preferably Fe,Al, or Al-Zr complexes; and n=1 to 20 PA1 Aci is selected from monovalent anionic group comprising: (a) Cl--, (b) Br--, (c)I--, (d) NO.sub.3 --, (e) CH.sub.3 COO--, (f) H.sub.2 Po.sub.4 --,(g) OH.sup.- or (h) a mixture of two or more of the foregoing, but preferably Aci is Cl--. PA1 I (b): Al.sub.m (OH).sub.n X.sub.3m-n-2k (SO.sub.4).sub.k PA1 I (c): Al.sub.1-x Fe.sub.x III Fe.sub.y II (OH).sub.3+2y-2 (Ha1).sub.z PA1 (x+y)/(1-x)=about 0.2 to 1.5. z&lt;3+2y, and (3+2y-2)/(3+2y)=about 0.24 to 0.67 PA1 I (d): Al.sub.m (OH).sub.x (SO.sub.4)y (H.sub.2 PO.sub.4).sub.z PA1 m and x are positive integers; PA1 y is 0 or a positive integer; and PA1 z is 0 or a positive integer. PA1 I (e): Me.sub.n (OH).sub.m X.sub.3n-m PA1 Me is a tri- or more valent metal, and X is Cl--, CH.sub.3 COO--, or NO.sub.3..sup.- or OH.sup.- PA1 I (f): Regular salts of aluminum, iron, titanium, vanadium, chromium, antimony such as chloride, sulfates, phosphates, nitrates, acetates or mixture thereof, sodium and/or potassium silicate, magnesium and/or calcium silicate, aluminum magnesium silicate, sodium, metasiliicate, bentonite and/or cationic bentonite, organic cationic modified bentonite or mixture thereof. PA1 1. Polyhydroxyaluminumchloride; Al.sub.4 (OH).sub.9 (Cl).sub.3, or Al.sub.8 (OH).sub.2 (Cl).sub.3, or Al.sub.11 (H).sub.30 (Cl).sub.3. PA1 2. Hydroxyaluminumchloride: Al.sub.2 (OH).sub.5 Cl as Chlorhydrol TR-50, Astrigen TR-50 PA1 3. Polyhydroxyaluminumagnesiumchloride: Al.sub.3 Mg(OH).sub.9 (Cl).sub.2; PA1 4. Polyhydroxyaluminumcalciumchloride: Al.sub.7 Ca.sub.0.04 (OH).sub.17.01 (Cl).sub.4 ; PA1 5. Polyhydroxyaluminumagnesiumsulfate: Al.sub.4 Mg(OH).sub.4 (SO.sub.4)3.5; PA1 6. Hydroxyaluminumsulfate: Al.sub.2 (OH).sub.4 SO.sub.4 ; PA1 7. Polyaluminumsulfate: (PAS) Al.sub.2 (OH).sub.2 (SO.sub.4).sub.2 PA1 8. Polyhydroxyaluminumzincoxidechloride: Al.sub.3 (OH).sub.3 ZnO(OH) (Cl).sub.5 ; PA1 9. Polyhydroxyaluminum and/or magnesiumchlorosulfate: Al.sub.4 (OH).sub.6 (Cl).sub.4 (SO.sub.4) or Al.sub.3 Mg(OH).sub.6 (Cl).sub.3 (SO); PA1 10. Polyaluminumferric and/or ferrous chloride: Al.sub.2 Fe.sub.2 (OH).sub.3.32 (Cl).sub.6.68 or Al Fe.sub.0.25.sup.II Fe.sub.0.25.sup.III (OH).sub.2.12 (Cl); PA1 11. Polyaluminumchloride sulfate, and PA1 12. Polyhydroxyaluminumchlorosilicate. PA1 13. Aluminumzirconium (penta or tetra) chlorohydrate: Al.sub.8 Zr(OH).sub.23 Cl.sub.5 or Al.sub.4 Zr(OH).sub.12 Cl.sub.4, etc. PA1 a. Polyamine-modified urea-formaldehyde resins and PA1 b. Melamine-formaldehyde resins, PA1 c. Any suitable polyamine and/or polyarylamide modifier can be used in the modified urea-formaldehyde resins such as, without limit: cyanoguanidine-diethylene triamine-melamine; reaction product of about one (1) Mole cyan three (3) Moles of formaldehyde and from about one (1) Mole of urea, per mole of said cyanogu reaction product of about 0.9 Mole of cyanoguanidine, about Mole of melamine, about three Moles of formaldehyde and from about 0.5 Mole to about one Mole of urea per Mole of said cyanoguanidine and melamine produced and the mixture of said resins one part to about nine (9) parts of polyamine and/or polyacrylamine, and/or one part by weight of said polyarylamine and about two (2) to nine (9) parts of weight of said aminoplast resins and/or cationic aminoplast resins.
Other paint-varnish systems which may be used are:
The treatment system commonly used is controlled additions of coagulants with simultaneous pH control which are removed by air flotation, electroflotation or sedimentation, slurryholding and filter press. In the case of air flotation, full chemical coagulant with good performance is still to be achieved. the regular ferric or aluminum sulfate, though largely unsuccessful for coagulation processes, are used as paint "killer". The industrial waste water and water-borne paints treated with the inorganic-organic and/or organic alloy polymer adducts have a high impact on coagulation processes. These act as primary coagulants which under neutralization processes (preferable "hydrophobe" compositions) will floc and kill the paint. Good performance was produced with an operating pH of 6.0 to 9.0 for anodic and cathodic paint which gives high supernatant clarity and high settling and/or dewatering rates. As pH can be used any reagents, or alkaline inorganic and/or organic matter but preferable are the hydrophobe alkaline agents. For the preparation of "hydrophobe" alkaline material, the following can be used:
For air and/or electroflotation, NaOH is the most commonly used, producing as well as hydrophobe agents in some cases, less dense and easily floated flocs. For anodic paint treatment, alkali dosage can be used before the coagulation addition, therefore the final pH is approached from the high pH end.
Polyelectrolyte selection is very important too. These must have very high molecular weight (Mw). In the case of water-borne paint waste water, a dosage of less than 1.0 ppm often improved supernatant clarity and fast settlement. Higher concentrations may tend to produce bulky, open-textured flocs.